Transmission power control method, and radio network controller

ABSTRACT

A transmission power control method for controlling a transmission power of an E-DPCCH, includes: determining, at a radio network controller, that a mobile station transmitting the E-DPCCH to only a first cell transmits the E-DPCCH to the first cell and a second cell; determining, at the radio network controller, an E-DPCCH Transmission Power Offset which is an offset from a transmission power of a DPCCH based on the determination; notifying, at the radio network controller, the E-DPCCH Transmission Power Offset to the mobile station; determining, at the mobile station, the transmission power of the E-DPCCH to be transmitted to the first cell and the second cell, based on the notified E-DPCCH Transmission Power Offset; and transmitting, at the mobile station, the E-DPCCH to the first cell and the second cell using the determined transmission power.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. P2005-274649, filed on Aug.24, 2005; the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a transmission power control method anda radio network controller.

2. Description of the Related Art

In a conventional mobile communication system, when setting a DedicatedPhysical Channel (DPCH) between a mobile station UE and a radio basestation Node B, a radio network controller RNC is configured todetermine a transmission rate of uplink user data, in consideration ofhardware resources for receiving of the radio base station Node B(hereinafter, hardware resource), a radio resource in an uplink (aninterference volume in an uplink), a transmission power of the mobilestation UE, a transmission processing performance of the mobile stationUE, a transmission rate required for an upper application, or the like,and to notify the determined transmission rate of the uplink user databy a message of a layer-3 (Radio Resource Control Layer) to both of themobile station UE and the radio base station Node B.

Here, the radio network controller RNC is provided at an upper level ofthe radio base station Node B, and is an apparatus configured to controlthe radio base station Node B and the mobile station UE.

In general, data communications often cause burst traffic compared withvoice communications or TV communications. Therefore, it is preferablethat a transmission rate of a channel used for the data communicationsis changed fast.

However, as shown in FIG. 1, the radio network controller RNC integrallycontrols a plurality of radio base stations Node B in general.Therefore, in the conventional mobile communication system, there hasbeen a problem that it is difficult to perform fast control for changingof the transmission rate of uplink user data (for example, perapproximately 1 through 100 ms), due to the increase of processing loadand processing delay in the radio network controller RNC.

In addition, in the conventional mobile communication system, there hasbeen also a problem that costs for implementing an apparatus and foroperating a network are substantially increased even if the fast controlfor changing of the transmission rate of the uplink user data can beperformed.

Therefore, in the conventional mobile communication system, control forchanging of the transmission rate of the uplink user data is generallyperformed on the order from a few hundred ms to a few seconds.

Accordingly, in the conventional mobile communication system, when burstdata transmission is performed as shown in FIG. 2A, the data aretransmitted by accepting low-speed, high-delay, and low-transmissionefficiency as shown in FIG. 2B, or, as shown in FIG. 2C, by reservingradio resources for high-speed communications to accept that radiobandwidth resources in an unoccupied state and hardware resources in theradio base station Node B are wasted.

It should be noted that both of the above-described radio bandwidthresources and hardware resources are applied to the vertical radioresources in FIGS. 2B and 2C.

Therefore, the 3rd Generation Partnership Project (3GPP) and the 3rdGeneration Partnership Project 2 (3GPP2), which are internationalstandardization organizations of the third generation mobilecommunication system, have discussed a method for controlling radioresources at high speed in a layer-1 and a media access control (MAC)sub-layer (a layer-2) between the radio base station Node B and themobile station UE, so as to utilize the uplink radio resourceseffectively. Such discussions or discussed functions will be hereinafterreferred to as “Enhanced Uplink (EUL)”.

Referring to FIG. 3, the mobile communication system, to which the“Enhanced Uplink” is applied, is explained.

In FIG. 3, the mobile station UE is establishing a radio link with onlya cell #10 controlled by the radio base station Node B #1 (hereinafter,the cell which is controlled by the radio base station Node B isindicated as cell).

Here, in FIG. 3, an example that the mobile station UE in a Non-SHOstate shifts to a SHO state where radio links with the cell #10 as wellas a cell #20 are established is shown.

In such a case, the mobile station UE is configured to determine atransmission power of an “Enhanced Dedicated Physical Control Channel(E-DPCCH)”, based on a transmission power ratio between a transmissionpower of a “Dedicated Physical Channel (DPCH)” to which a closed looptransmission power control is performed and a transmission power of anE-DPCCH.

Here, the radio link includes the DPCH or an “Enhanced DedicatedPhysical Channel (E-DPCH)” between the mobile station UE and the radiobase station Node B.

In step S2001, the mobile station UE is establishing a data connection(E-DPDCH) for transmitting the uplink user data with the radio networkcontroller RNC via the cell #10.

In step S2002, when the reception power of a common pilot channel fromthe cell #20 become more than or equal to the predetermined value, themobile station UE transmits measurement report to the radio networkcontroller RNC.

In step S2003, the radio network controller RNC requests the radio basestation Node B #2 controlling the cell #20 to establish synchronizationof radio links for uplink between the mobile station UE and the cell#20, based on the transmitted measurement report.

To be more specific, in step S2003, the radio network controller RNCtransmits, to the radio base station Node B #2, a SHO setting requestincluding SHO parameters. For example, the SHO parameters include astart time of the SHO.

In step S2004, the cell #20 transmits a SHO setting response forindicating that the cell #20 has received the SHO setting request.

In step S2005, the radio network controller RNC requests the mobilestation UE to establish synchronization of radio links for downlinkbetween the cell #20 and the mobile station UE.

To be more specific, in step S2005, the radio network controller RNCtransmits, to the mobile station UE, a SHO setting request including theSHO parameters. In step S2006, the mobile station UE transmits a SHOsetting response for indicating that the mobile station UE has receivedthe SHO setting request.

The mobile station UE shifts from the Non-SHO state to the SHO statebased on the SHO parameters. In step S2007, the mobile station becomesin the SHO state with the cell #10 and the cell #20.

Based on the above steps, the mobile station UE in the EUL is configuredto connect to a plurality of cells simultaneously in the SHO state, soas to prevent the interruption of communication.

Here, with regard to a certain mobile station US, a set of radio linksestablished between the mobile station UE and the cell controlled by theradio base station Node B will be called as an “active set”.

The active set will be updated, for example, when the mobile station UEshifts between the Non-SHO state and the SHO state, or when the cells towhich the mobile station UE establishes radio links are changed.

However, in the above method, when the active set is updated, theE-DPCCH transmission power offset, which is used to determine thetransmission power required to receive, at the radio base station NodeB, the E-DPCCH from the mobile station UE, will be drastically changed.Accordingly, the radio base station Node B cannot receive the E-DPCCHfrom the mobile station UE.

Further, there has been a problem that if the radio base station Node Bcannot receive the E-DPCCH from the mobile station UE, the radio basestation Node B cannot transmit ACK/NACK to the mobile station UE.

In such case, the probability of falsely detecting the ACK increases inthe mobile station UE, and the probability that the mobile station UEtransmits the subsequent uplink user data when it should haveretransmitted the previous data increases. Accordingly, the data lossrate is increased, and the transmission efficiency will deterioratedrastically.

BRIEF SUMMARY OF THE INVENTION

The present invention has been made considering the problems, and itsobject is to provide a transmission power control method which enablesto certainly transmit an E-DPCCH to a radio base station Node B when anactive set is updated, so as to realize a stable radio communication foruplink, and to reduce a deterioration of radio network capacity, and aradio network controller.

A first aspect of the present invention is summarized as a transmissionpower control method for controlling a transmission power of an EnhancedDedicated Physical Control Channel, includes: determining, at a radionetwork controller, that a mobile station transmitting the EnhancedDedicated Physical Control Channel to only a first cell transmits theEnhanced Dedicated Physical Control Channel to the first cell and asecond cell; determining, at the radio network controller, an EnhancedDedicated Physical Control Channel transmission power offset which is anoffset from a transmission power of a dedicated physical control channelbased on the determination; notifying, at the radio network controller,the Enhanced Dedicated Physical Control Channel transmission poweroffset to the mobile station, determining, at the mobile station, thetransmission power of the Enhanced Dedicated Physical Control Channel tobe transmitted to the first cell and the second cell, based on thenotified Enhanced Dedicated Physical Control Channel transmission poweroffset; and transmitting, at the mobile station, the Enhanced DedicatedPhysical Control Channel to the first cell and the second cell using thedetermined transmission power.

A second aspect of the present invention is summarized as a radionetwork controller used in a mobile communication system in which amobile station controls a transmission power of an Enhanced DedicatedPhysical Control Channel, including: a determiner configured todetermine that a mobile station transmitting the Enhanced DedicatedPhysical Control Channel to only a first cell transmits the EnhancedDedicated Physical Control Channel to the first cell and a second cell;an offset determiner configured to determine an Enhanced DedicatedPhysical Control Channel transmission power offset which is an offsetfrom a transmission power of a dedicated physical control channel basedon the determination; and an offset notifier configured to notify theEnhanced Dedicated Physical Control Channel transmission power offset tothe mobile station.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is diagram of an entire configuration of a general mobilecommunication system.

FIGS. 2A to 2C are diagrams for explaining a method for controlling atransmission rate of uplink used data in a conventional mobilecommunication system.

FIG. 3 is a diagram for explaining the transmission rate control methodin the conventional mobile communication system.

FIG. 4 is a diagram of an entire configuration of mobile communicationsystem according to a first embodiment of the present invention.

FIG. 5 is a functional block diagram of a mobile station in the mobilecommunication system according to the first embodiment of the presentinvention.

FIG. 6 is a functional block diagram of a baseband signal processingsection of the mobile station in the mobile communication systemaccording to the first embodiment of the present invention.

FIG. 7 is a diagram for explaining functions of the baseband signalprocessing section of the mobile station in the mobile communicationsystem according to the first embodiment of the present invention.

FIG. 8 is a functional block diagram of a MAC-e functional section inthe baseband signal processing section of the mobile station in themobile communication system according to the first embodiment of thepresent invention.

FIG. 9 is a functional block diagram of a layer-1 functional section inthe baseband signal processing section of the mobile station in themobile communication system according to the first embodiment of thepresent invention.

FIG. 10 is a diagram for explaining functions of the layer-1 functionalsection in the baseband signal processing section of the mobile stationin the mobile communication system according to the first embodiment ofthe present invention.

FIG. 11 is a functional block diagram of a radio base station accordingto the first embodiment of the present invention.

FIG. 12 is a functional block diagram of a baseband signal processingsection in the radio base station of the mobile communication systemaccording to the first embodiment of the present invention.

FIG. 13 is a functional block diagram of a layer-1 functional section inthe baseband signal processing section in the radio base station of themobile communication system according to the first embodiment of thepresent invention.

FIG. 14 is a functional block diagram of a MAC-e functional section inthe baseband signal processing section in the radio base station of thecommunication system according to the first embodiment of the presentinvention.

FIG. 15 is a functional block diagram of a radio network controller ofthe mobile communication system according to the first embodiment of thepresent invention.

FIG. 16 is a sequence diagram showing operations of a transmission ratecontrol method in the mobile communication system according to the firstembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Configuration of MobileCommunication System According to First Embodiment of the PresentInvention

Referring to FIGS. 4 to 16, a configuration of a mobile communicationsystem according to a first embodiment of the present invention will bedescribed.

It should be noted that, the mobile communication system according tothis embodiment is designed in order to increase a communicationperformance such as a communication capacity, a communication qualityand the like. Further, the mobile communication system according to thisembodiment can be applied to “W-CDMA” and “CDMA2000” of the thirdgeneration mobile communication system.

In the example of FIG. 4, the cell #3 controlled by the radio basestation Node B #1, which has received a “Dedicated Physical Channel(hereinafter, DPCH)” transmitted from the mobile station UE, isconfigured to determine an increase/decrease of a transmission power ofthe DPCH in the mobile station UE, based on the reception power of theDPCH, and to transmit the result of increase/decrease of thetransmission power of the DPCH to the mobile station UE, by using TPCcommand (for example, Up Command, Down Command).

Further, the radio base station Node B #1 which controls the cell #3 isconfigured to control the transmission power of the DPCH fortransmitting to the mobile station UE, by using the TPC commandtransmitted from the mobile station UE.

Furthermore, the mobile station UE is configured to determine thetransmission power of an “Enhanced Dedicated Physical Control Channel(E-DPCCH)” to be transmitted to the cell #3, based on the EnhancedDedicated Physical Control Channel transmission power offset(hereinafter, E-DPCCH transmission power offset).

An example of general configuration of a mobile station UE according tothis embodiment is shown in FIG. 5.

As shown in FIG. 5, the mobile station UE is provided with a businterface 11, a call processing control section 12, a baseband signalprocessing section 13, a transmitter-receiver section 14, and atransmission-reception antenna 15. In addition, the mobile station UEcan be configured to include an amplifier section (not shown in FIG. 5).

However, these functions do not have to be independently present ashardware. That is, these functions can be partly or entirely integrated,or can be configured through a process of software.

In FIG. 6, a functional block of the baseband signal processing section13 is shown.

As shown in FIG. 6, the baseband signal processing section 13 isprovided with an upper layer functional section 131, a RLC functionalsection 132, a MAC-d functional section 133, a MAC-e functional section134, and a layer-1 functional section 135.

The RLC functional section 132 is configured to work as RLC sublayer.The layer-1 functional section 135 is configured to work as a layer-1.

As shown in FIG. 7, the RLC functional section 132 is configured todivide an application data (RLC SDU), which is received from the upperlayer functional section 131, into PDUs of a predetermined PDU size.Then, the RLC functional section 132 is configured to generate RLC PDUsby adding a RLC header used for a sequence control processing,retransmission processing, and the like, so as to pass the RLC PDUs tothe MAC-d functional section 133.

Here, a pipeline works as a bridge between the RLC functional section132 and the MAC-d functional section 133 is a “logical channel”. Thelogical channel is classified based on the contents of data to betransmitted/received, and when a communication is performed, it ispossible to establish a plurality of logical channels in one connection.In other words, when the communication is performed, it is possible totransmit/receive a plurality of data with different contents (forexample, control data and user data, or the like) logically in parallel.

The MAC-d functional section 133 is configured to multiplex the logicalchannels, and to add a MAC-d header associated with the multiplex of thelogical channels, so as to generate a MAC-d PDU. A plurality of MAC-dPDUs are transferred from the MAC-d functional section 133 to the MAC-efunctional section 134 as MAC-d flow.

The MAC-e functional section 134 is configured to assemble a pluralityof MAC-d PDUs which are received from the MAC-d functional section 133as MAC-d flow, and to add a MAC-e header to the assembled MAC-d PDU, soas to generate a transport block. Then, the MAC-e functional section 134is configured to pass the generated transport block to the layer-1functional section 135 through a transport channel.

In addition, the MAC-e functional section 134 is configured to work as alower layer of the MAC-d functional section 133, and to implement theretransmission control function according to Hybrid ARQ (HARQ) and thetransmission rate control function specifically, as shown in FIG. 8, theMAC-e functional section 134 is provided with a multiplex section 134 a,an E-TFC selecting section 134 b, and an HARQ processing section 134 c.

The multiplex section 134 a is configured to perform a multiplexprocessing to the uplink user data, which is received from the MAC-dfunctional section 133 as MAC-d flow, based on a “Enhanced-TransportFormat Indicator (E-TFI)” notified from the E-TFC selecting section 134b, so as to generate uplink user data (a Transport Block) to betransmitted via a transport channel (E-DCH). Then, the multiplex section134 a is configured to transmit the generated uplink user data(Transport Block) to the HARQ processing section 134 c.

Hereinafter, the uplink user data received as MAC-d flow is indicated asthe “uplink user data (MAC-d flow)”, and the uplink user data to betransmitted via the transport channel (E-DCH) is indicated as the“uplink user data (E-DCH)”.

The E-TFI is an identifier of a transport format, which is a format forproviding the transport block on the transport channel (E-DCH) per TTI,and the E-TFI is added to the MAC-e header.

The multiplex section 134 a is configured to determine a transmissiondata block size to be applied for the uplink user data based on theE-TFI notified from the E-TFC selecting section 134 b, and to notify thedetermined transmission data block size to the HARQ processing section134 c.

In addition, when the multiplex section 134 a receives the uplink userdata from the MAC-d functional section 133 as MAC-d flow, the multiplexsection 134 a is configured to notify, to the E-TFC selecting section134 b, E-TFC selecting information for selecting a transport format forthe received uplink user data.

Here, the E-TFC selecting information includes data size and priorityclass of the uplink user data, or the like.

The HARQ processing section 134 c is configured to perform theretransmission control processing for the “uplink user data (E-DCH)”according to the “N channel stop and wait (N-SAW) protocol”, based onACK/NACK for the uplink user data notified from the layer-1 functionalsection 135.

In addition, the HARQ processing section 134 c is configured totransmit, to the layer-1 functional section 135, the “uplink user data(E-DCH)” received from the multiplex section 134 a, and HARQ information(for example, a number for retransmission, and the like) used for theHARQ processing.

The E-TFC selecting section 134 b is configured to determine thetransmission rate of the uplink user data by selecting the transportformat (E-TF) to be applied to the “uplink user data (E-DCH)”.

Specifically, the E-TFC selecting section 134 b is configured todetermine whether the transmission of the uplink user data should beperformed or stopped, based on scheduling information, the amount ofdata in MAC-d PDU, the condition of hardware resource of the radio basestation Node B, and the like.

The scheduling information (such as absolute transmission rate and arelative transmission rate of the uplink user data) is received from theradio base station Node B, the amount of data in MAC-d PDU (such as datasize of the uplink user data) is passed from the MAC-d functionalsection 133, and the condition of hardware resource of the radio basestation Node B is controlled in the MAC-e functional section 134.

Then, the E-TFC selection section 134 b is configured to select thetransport format (E-TF) to be applied to transmission of the uplink userdata, and to notify the E-TFI for identifying the selected transportformat to the layer-1 functional section 135 and the multiplex section134 a.

For example, the E-TFC selecting section 134 b is configured to storethe transmission rate of uplink user data in association with thetransport format, to update the transmission rate of uplink user databased on the scheduling information from the layer-1 functional section135, and to notify, to the layer-1 functional section 135 and themultiplex section 134 a, the E-TFI for identifying the transport formatwhich is associated with the updated transmission rate of uplink userdata.

Here, when the E-TFC selecting section 134 b receives the absolutetransmission rate of the uplink user data from the serving cell for themobile station UE via the E-AGCH as the scheduling information, theE-TFC selecting section 134 b is configured to change the transmissionrate of the uplink user data to the received absolute transmission rateof the uplink user data.

In addition, when the E-TFC selecting section 134 b receives therelative transmission rate of the uplink user data (Down command orDon't care command) from the non-serving cell for the mobile station UEvia the E-RGCH as the scheduling information, the E-TFC selectingsection 134 b is configured to increase/decrease the transmission rateof the uplink user data, at the timing of receiving the relativetransmission rate, by the predetermined rate based on the relativetransmission rate of the uplink user data.

In this specification, the transmission rate of the uplink user data canbe a rate which can transmit an uplink user data via an “EnhancedDedicated Physical Data Channel (E-DPDCH)”, a transmission data blocksize (TBS) for transmitting an uplink user data, a transmission power ofan “E-DPDCH”, or a transmission power ratio (a transmission poweroffset) between an “E-DPDCH” and a “Dedicated Physical Control Channel(DPCCH)”.

As shown in FIG. 9, the layer-1 functional section 135 is provided witha transmission channel encoding section 135 a, a physical channelmapping section 135 b, a DPDCH transmitting section 135 c 1, a DPCCHtransmitting section 135 c 2, an E-DPDCH transmitting section 135 d, anE-DPCCH transmitting section 135 e, an E-HICH receiving section 135 f,an E-RGCH receiving section 135 g, an E-AGCH receiving section 135 h, aphysical channel de-mapping section 135 j, and a DPCH receiving section135 i.

As shown in FIG. 10, the transmission channel encoding section 135 a isprovided with a FEC (Forward Error Correction) encoding section 135 a 1,and a transmission rate matching section 135 a 2.

As shown in FIG. 10, the FEC encoding section 135 a 1 is configured toperform the error correction encoding processing toward the “uplink userdata (E-DCH)”, that is, the transport block, transmitted from the MAC-efunctional section 134.

In addition, as shown in FIG. 10, the transmission rate matching section135 a 2 is configured to perform, toward the transport block to whichthe error correction encoding processing is performed, the processing of“repetition (repeat of bit)” and “puncture (bit skipping)” in order tomatch to the transmission capacity in the physical channel.

The physical channel mapping section 135 b is configured to pair the“uplink user data (E-DCH)” from the transmission channel encodingsection 135 a with the E-DPDCH, and to pair the E-TFI and the HARQinformation from the transmission channel encoding section 135 a withthe E-DPCCH.

The DPDCH transmitting section 135 c 1 is configured to perform atransmission processing of a “Dedicated Physical Data Channel (DPDCH)”for uplink user data. The DPDCH is used for transmitting the uplink userdata to be transmitted by the mobile station UE.

Here, the above uplink user data includes a measurement report, whichreports transmission power of a common pilot channel transmitted fromthe cell.

The DPCCH transmitting section 135 c 2 is configured to perform atransmission processing of a “Dedicated Physical Control Channel(DPCCH)” for uplink. The transmission power of the DPCCH for uplink iscontrolled by the transmission power control method using the TPCcommand.

The E-DPDCH transmitting section 135 d is configured to perform atransmission processing of the E-DPDCH.

The E-DPCCH transmitting section 135 e is configured to perform atransmission processing of the E-DPCCH.

Furthermore, the E-DPCCH transmitting section 135 e is configured totransmit the E-DPCCH using the transmission power determined based onthe E-DPCCH transmission power offset.

The E-HICH receiving section 135 f is configured to receive an “E-DCHHARQ Acknowledgement Indicator Channel (E-HICH)” transmitted from thecells (the serving cell and the non-serving cell for the mobile stationUE).

The E-RGCH receiving section 135 g is configured to receive the E-RGCHtransmitted from the cells (the serving cell and the non-serving cellfor the mobile station UE).

The E-AGCH receiving section 135 h is configured to receive the E-AGCCHtransmitted from the cell (the serving cell for the mobile station UE).

The physical channel de-mapping section 135 j is configured to extractthe scheduling information (the relative transmission rate of the uplinkuser data, that is, Up command/Down command/Don't care command) which isincluded in the E-RGCH received by the E-RGCH receiving section 135 g,so as to transmit the extracted scheduling information to the MAC-efunctional section 134.

In addition, the physical channel de-mapping section 135 j is configuredto extract the scheduling information (the absolute transmission rate ofthe uplink user data) which is included in the E-AGCH received by theE-AGCH receiving section 135 h, so as to transmit the extractedscheduling information to the MAC-e functional section 134.

The DPCH receiving section 135 i is configured to perform a receiveprocessing of a downlink “Dedicated Physical Channel (DPCH)” transmittedfrom the cell.

Here, the DPCH includes a “Dedicated Physical Data channel (DPDCH)” anda “Dedicated Physical Control Channel (DPCCH)”.

FIG. 11 shows an example of a configuration of functional blocks of aradio base station Node B according to this embodiment.

As shown in FIG. 11, the radio base station Node B according to thisembodiment is provided with an HWY interface 21, a baseband signalprocessing section 22, a transmitter-receiver section 23, an amplifiersection 24, a transmission-reception antenna 25, and a call processingcontrol section 26.

The HWY interface 21 is configured to receive downlink user data to betransmitted from the radio network controller RNC, which is located inan upper level of the radio base station Node B, so as to enter thereceived downlink user data to the baseband signal processing section22.

In addition, the HWY interface 21 is configured to transmit uplink userdata from the baseband signal processing section 22 to the radio networkcontroller RNC.

The baseband signal processing section 22 is configured perform thelayer-1 processing such as channel encoding processing, spreadingprocessing, and the like, to the downlink user data, so as to transmitthe baseband signal including the downlink user data to thetransmitter-receiver section 23.

In addition, the baseband Signal processing section 22 is configured toperform the layer-1 processing such as despreading processing, RAKEcombining processing, error correction decoding processing, and thelike, to the baseband signal, which is acquired from thetransmitter-receiver section 23, so as to transmit the acquired uplinkuser data to the HWY interface 21.

The transmitter-receiver section 23 is configured to convert thebaseband signal, which is acquired from the baseband signal processingsection 22, to radio frequency signals.

In addition, the transmitter-receiver section 23 is configured toconvert the radio frequency signals, which are acquired from theamplifier section 24, to the baseband signals.

The amplifier section 24 is configured to amplify the radio frequencysignals acquired from the transmitter-receiver section 23, so as totransmit the amplified radio frequency signals to the mobile station UEvia the transmission-reception antenna 25.

In addition, the amplifier section 24 is configured to amplify thesignals received by the transmission-reception antenna 25, so as totransmit the amplified signals to the transmitter-receiver section 23.

The call processing control section 26 is configured to transmit/receivethe call processing control signals to/from the radio network controllerRNC, and to perform the processing of condition control of each functionin the radio base station Node B, allocating hardware resource inlayer-3, and the like.

FIG. 12 is a functional block diagram of the baseband signal processingsection 22.

As shown in FIG. 12, the baseband signal processing section 22 isprovided with a layer-1 functional section 221, and a MAC-e functionalsection 222.

As shown in FIG. 13, the layer-1 functional section 221 is provided witha DPDCH despreading-RAKE combining section 221 a 1, a DPDCH decodingsection 221 b 1, a DPCCH despreading-RAKE combining section 221 a 2, aDPCCH decoding section 221 b 2, an E-DPCCH despreading-RAKE combiningsection 221 c, E-DPCCH decoding section 221 d, an E-DPDCHdespreading-RAKE combining section 221 e, a buffer 221 f, are-despreading section 221 g, an HARQ buffer 221 h, an error correctiondecoding section 221 i, a transmission channel encoding section 221 j, aphysical channel mapping section 221 k, an E-HICH transmitting section221 l, an E-AGCH transmitting section 221 m, an E-RGCH transmittingsection 221 n, and a DPCH transmitting section 221 o.

However, these functions do not have to be independently present ashardware. That is, these functions can be partly or entirely integrated,or can be configured through a process of software.

The DPDCH despreading-RAKE combining section 221 a 1 is configured toperform the despreading processing and the RAKE combining processing tothe DPDCH.

The DPDCH decoding section 221 b 1 is configured to decode the uplinkuser data transmitted from the mobile station UE, based on the outputfrom the DPDCH despreading-RAKE combining section 221 a 1, so as totransmit the decoded uplink user data to the MAC-e functional section222.

Here, the above uplink user data includes a measurement report, whichreports reception power of a common pilot channel transmitted from themobile station UE.

The DPCCH despreading-RAKE combining section 221 a 2 is configured toperform the despreading processing and the RAKE combining processing tothe DPCCH.

The DPCCH decoding section 221 b 2 is configured to decode the uplinkcontrol information transmitted from the mobile station UE, based on theoutput from the DPCCH despreading-RAKE combining section 221 a 2, so asto transmit the decoded uplink control information to the MAC-efunctional section 222.

The E-DPCCH despreading-RAKE combining section 221 c is configured toperform the despreading processing and RAKE combining processing to theE-DPCCH.

The E-DPCCH decoding section 221 d is configured to decode the E-TFCIfor determining the transmission rate of the uplink user data (or an“Enhanced Transport Format and Resource Indicator (E-TFRI)” based on theoutput from the E-DPCCH despreading-RAKE combining section 221 c, so asto transmit the decoded E-TFCI to the MAC-e functional section 222.

The E-DPDCH despreading-RAKE combining section 221 e is configured toperform the despreading processing to the E-DPDCH using the spreadingfactor (the minimum spreading factor) and the number of multi-codeswhich correspond to the maximum rate that the E-DPDCH can use, so as tostore the despread data to the buffer 221 f. By performing thedespreading processing using the above described spreading factor andthe number of multi-codes, it is possible for the radio base stationNode B to reserve the resources so that the radio base station Node Bcan receive the uplink data up to the maximum rate (bit rate) that themobile station UE can use.

The re-despreading section 221 g is configured to perform there-despreading processing to the data stored in the buffer 221 f usingthe spreading factor and the number of multi-codes which are notifiedfrom the MAC-e functional section 222, so as to store the re-despreaddata to the HARQ buffer 221 h.

The error correction decoding section 221 i is configured to perform theerror correction decoding processing to the data stored in the HARQbuffer 221 h based on the coding rate which is notified from the MAC-efunctional section 222, so as to transmit the acquired “uplink user data(E-DCH)” to the MAC-e functional section 222.

The transmission channel encoding section 221 j is configured to performthe necessary encoding processing to the ACK/ACK and the schedulinginformation for the uplink user data received from the MAC-e functionalsection 222.

The physical channel mapping section 221 k is configured to pair theACK/NACK for the uplink user data, which is acquired from thetransmission channel encoding section 221 j, with the E-HICH, to pairthe scheduling information (absolute transmission rate), which isacquired from the transmission channel encoding section 221 h, with theE-AGCH, and to pair the scheduling information (relative transmissionrate), which is acquired from the transmission channel encoding section221 j, with the E-RGCH.

The E-HICH transmitting section 221 l is configured to perform atransmission processing of the E-HICH.

The E-AGCH transmitting section 221 m is configured to perform atransmission processing to the E-AGCH.

The E-RGCH transmitting section 221 n is configured to perform atransmission processing to the E-RGCH.

The DPCH transmitting section 221 o is configured to perform atransmission processing to a downlink “Dedicated Physical Channel(DPCH)” transmitted from the radio base station Node B.

As shown in FIG. 14, the MAC-e functional section 222 is provided withan HARQ processing section 222 a, a receive processing command section222 b, a scheduling section 222 c, and a de-multiplex section 222 d.

The HARQ processing section 222 a is configured to receive the uplinkuser data and the HARQ information which are received from the layer-1functional section 221, so as to perform the HARQ processing on the“uplink user data (E-DCH)”.

In addition, the HARQ processing section 222 a is configured to notify,to the layer-1 functional section 221, the ACK/NACK (for the uplink userdata) which shows the result of receive processing on the “uplink userdata (E-DCH)”.

In addition, the HARQ processing section 222 a is configured to notify,to the scheduling section 222 c, the ACK/NACK (for the uplink user data)per process.

The receive processing command section 222 b is configured to notify, tothe re-despreading section 221 g and the HARQ buffer 221 h, thespreading factor and the number of multi-codes for the transport formatof each mobile station UE, which is specified by the E-TFCI per TTIreceived from the E-DPCCH decoding section 221 b in the layer-1functional section 221. Then, the receive processing command section 222b is configured to notify the encoding rate to the error correctiondecoding section 221 i.

The scheduling section 222 c is configured to change the absolutetransmission rate or the relative transmission rate of the uplink userdata, based on the E-TFCI per TTI received from the E-DPCCH decodingsection 221 d in the layer-1 functional section 221, the ACK/NACK perprocess received from the HARQ processing section 222 a, theinterference level, and the like.

In addition, the scheduling section 222 c is configured to notify, tothe layer-1 functional section 221, the absolute transmission rate orthe relative transmission rate of the uplink user data, as thescheduling information.

The de-multiplex section 222 d is configured to perform the de-multiplexprocessing to the “uplink user data (E-DCH and DCH)” received from theHARQ processing section 222 a, so as to transmit the acquired uplinkuser data to the HWY interface 21.

Here, the above uplink user data includes a measurement report, whichreports reception power of a common pilot channel transmitted from themobile station UE.

The radio network controller RNC according to this embodiment is anapparatus located in an upper level of the radio base station Node B,and is configured to control radio communications between the radio basestation Node B and the mobile station UE.

As shown in FIG. 15, the radio network controller RNC according to thisembodiment is provided with an exchange interface 31, a Logical LinkControl (LLC) layer functional section 32, a MAC layer functionalsection 33, a media signal processing section 34, a radio base stationinterface 35, and a call processing control section 36.

The exchange interface 31 is an interface with an exchange 1, and isconfigured to forward the downlink signals transmitted from the exchange1 to the LLC layer functional section 32, and to forward the uplinksignals transmitted from the LLC layer functional section 32 to theexchange 1.

The LLC layer functional section 32 is configured to perform an LLCsub-layer processing such as a combining processing of a header or atrailer such as a sequence pattern number.

The LLC layer functional section 32 is also configured to transmit theuplink signals to the exchange interface 31 and to transmit the downlinksignals to the MAC layer functional section 33, after the LLC sub-layerprocessing is performed.

The MAC layer functional section 33 is configured to perform a MAC layerprocessing such as a priority control processing or a header addingprocessing.

The MAC layer functional section 33 is also configured to transmit theuplink signals to the LLC layer functional section 32 and to transmitthe downlink signals to the radio base station interface 35 (or themedia signal processing section 34), after the MAC layer processing isperformed.

The media signal processing section 34 is configured to perform a mediasignal processing against voice signals or real time image signals.

The media signal processing section 34 is also configured to transmitthe uplink signals to the MAC layer functional section 33 and totransmit the downlink signals to the radio base station interface 35,after the media signal processing is performed.

The radio base station interface 35 is an interface with the radio basestation Node B. The radio base station interface 35 is configured toforward the uplink signals transmitted from the radio base station NodeB to the MAC layer functional section 33 (or the media signal processingsection 34) and to forward the downlink signals transmitted from the MAClayer functional section 33 (or the media signal processing section 34)to the radio base station Node B.

The call processing control section 36 is configured to perform a radioresource control processing, a channel setup and release processing bythe layer-3 signaling, or the like. Here, the radio resource controlincludes call admission control, handover control, or the like.

In addition, the call processing control section 36 is configured to setthe E-DPCCH transmission power offset, which is an offset from thetransmission power of the DPCCH, and to transmit the E-DPCCHtransmission power offset to the mobile station UE.

Operations of Mobile Communication System According to First Embodimentof the Present Invention

Referring to FIG. 16, operations of a transmission power control methodin the mobile communication system according to this embodiment will bedescribed.

To be more specific, an example in which the mobile station UE hasshifted from a Non-SHO state to a SHO state based on the transmissionpower control method according to this embodiment will be described.

In the transmission power control method according to this embodiment,the active set can be changed based on the predetermined conditionsother than the above mentioned cases, so as to change the cells whichestablish radio links with the mobile station UE, or decrease the numberof cells which establish radio links with the mobile station UE.

Here, a radio base station Node B according to this embodiment isconfigured to control one or a plurality of cells. In addition, in thisembodiment, the cells include the functions of the radio base stationNode B.

Here, the radio links according to this embodiment indicate the DPCH orthe E-DPDCH between the mobile station UE and the cell.

Therefore, in this embodiment, the state in which the mobile station isestablishing the radio link with only one cell is referred to “a Non-SHOstate”, and the state in which the mobile station UE is establishing theradio links with plurality of cells is referred to “a SHO state”.

Further, in this embodiment, it can be configured that both of cell #10and cell #20 are controlled by a same single radio base station Node B,or the each of cell #10 and cell #20 is controlled by different radiobase stations Node B.

As shown in FIG. 16, in step S1001, the mobile station UE isestablishing a data connection for transmitting the uplink user datawith the radio network controller RNC via the cell #10.

In step S1002, when the reception power of the common pilot signal fromthe cell #20 become more than or equal to the redetermined value, themobile station UE transmits a measurement report to the radio networkcontroller RNC.

The radio network controller RNC determines that the mobile station UEshifts to the SHO state, where the radio links with the cell #10 as wellas the cell #20 are established, based on the measurement report fromthe mobile station UE.

In step S1003, the radio network controller RNC transmits, to the cell#20, a SHO setting request which requests the cell #20 to establishsynchronization of radio links for uplink between the mobile station UEand the cell #20.

To be more specific, in step S1003, the radio network controller RNCtransmits, to the radio base station Node B #2, a SHO setting requestincluding SHO parameters. For example, the SHO parameters include astart time of the SHO, a channelization code for identifying a channelconfiguration of the radio links for the uplink, and a scrambling codefor identifying the mobile station UE.

In step S1004, the cell #20 transmits a SHO setting response forindicating that the cell #20 has received the SHO setting request.

In step S1005, the radio network controller RNC requests the mobilestation UE to establish synchronization of radio links for downlinkbetween the cell #20 and the mobile station UE.

To be more specific, in step S1005, the radio network controller RNCtransmits, to the mobile station UE, a SHO setting request including theSHO parameters For example, the SHO parameters includes a start time ofthe SHO, a channelization code for identifying a channel configurationof the radio links for the uplink, a scrambling code for identifying themobile station UE, and the E-DPCCH transmission power offset.

In step S1006, the mobile station UE transmits a SHO setting responsefor indicating that the mobile station UE has received the SHO settingrequest.

The mobile station UE shifts from the Non-SHO state to the SHO statebased on the parameters. In step S1007, the mobile station in the SHOstate with the cell #10 and the cell #20.

Effects of Mobile Communication System according to First Embodiment ofthe Present Invention

As described above, according to the present invention, it is possibleto provide a transmission power control method which enables tocertainly transmit an E-DPCCH to a radio base station Node B when anactive set is updated, to realize a stable radio communication foruplink, and to reduce a deterioration of radio network capacity, and aradio network controller.

In other words, the radio network controller RNC notifies an E-DPCCHtransmission power offset to the mobile station UE before the mobilestation UE shifts to the SHO state, so that the radio network controllerRNC can transmit the E-DPCCH certainly even after the mobile station UEhas shifted to the SHO state. Therefore, according to the transmissionpower control method and the radio network controller RNC, it ispossible to realize a stable radio communication for uplink, and toreduce a deterioration of radio network capacity.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and the representative embodimentsshown and described herein. Accordingly, various modifications may bemade without departing from the scope of the general inventive conceptas defined by the appended claims and their equivalents.

1. A transmission power control method for controlling a transmissionpower of an uplink enhanced dedicated physical control channel,comprising: determining, at a radio network controller, that a mobilestation transmitting the uplink enhanced dedicated physical controlchannel to only a first cell shifts to a soft handover state andtransmits the uplink enhanced dedicated physical control channel to boththe first cell and a second cell; determining, at the radio networkcontroller, an uplink power offset between a desired transmission powerof the uplink enhanced dedicated physical control channel and thetransmission power of an uplink dedicated physical control channel;notifying, from the radio network controller to the mobile station, theuplink power offset; determining, at the mobile station, an updatedtransmission power of the uplink enhanced dedicated physical controlchannel to be transmitted to the first cell and the second cell based onthe notified uplink power offset; and transmitting, at the mobilestation, the uplink enhanced dedicated physical control channel to thefirst cell and the second cell using the updated transmission power. 2.The user data transmission method according to claim 1, wherein theradio network controller determines that the mobile station shifts tothe soft handover state; the radio network controller transmits a softhandover setting request to the mobile station based on the firstdetermination; the mobile station shifts to the soft handover stateafter the mobile station receives the soft handover setting request; andthe soft handover setting request includes the uplink power offset.
 3. Aradio network controller used in a mobile communication system in whicha mobile station controls a transmission power of an uplink enhanceddedicated physical control channel, comprising: a determiner configuredto make a first determination that a mobile station transmitting theuplink enhanced dedicated physical control channel to only a first cellshifts to a soft handover state and transmits the uplink enhanceddedicated physical control channel to the first cell and a second cell;an offset determiner configured to determine an uplink power offsetbetween a desired transmission power of the uplink enhanced dedicatedphysical control channel and the transmission power of an uplinkdedicated physical control channel based on the first determination; andan offset notifier configured to notify the power offset to the mobilestation.
 4. A transmission power control method for controlling atransmission power of an uplink enhanced dedicated physical controlchannel, comprising: making a first determination, at a radio networkcontroller, of an update of an active set of cells for a mobile station;determining, at the radio network controller, an uplink power offsetbetween a desired transmission power of the uplink enhanced dedicatedphysical control channel and the transmission power of an uplinkdedicated physical control channel based on the first determination;notifying, from the radio network controller to the mobile station, theuplink power offset; determining, at the mobile station, an updatedtransmission power of the enhanced dedicated physical control channel tobe transmitted to a cell included in the updated active set, based onthe notified first power offset; and transmitting, at the mobilestation, the enhanced dedicated physical control channel to at least onecell included in the updated active set of cells using the updatedtransmission power.
 5. A transmission power control method forcontrolling a transmission power of an uplink enhanced dedicatedphysical control channel, comprising: a radio network controllerdetermining that a mobile station will be shifting to a soft handoverstate; the radio network controller calculating an uplink power offsetbetween a desired transmission power of the uplink enhanced dedicatedphysical control channel and the transmission power of an uplinkdedicated physical control channel based on the first determination,wherein the uplink power offset is based on radio links to be utilizedby the mobile station during soft handover; the radio network controllersending a soft handover settings request to a base station that includesthe uplink power offset; a radio network controller requesting themobile station to synchronize a radio link with the base station to aradio link with a different base station based on the uplink poweroffset; and the mobile station transmitting an uplink enhanced dedicatedphysical control channel to the base station at a power based on theuplink power offset during the soft handover state.